Series shunt for dynamo-electric machines.



15I0.8'70,611.v ,y PATBNTBD Nov. 12, 1907.

H. G. BEBKLBY.-

SERIES SHUNT POR DYNAMO ELECTRIC MACHINES.

APLIoATIoN FILED Nov,l 29., 1905.

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un irnn 'serres HENRXv CLYDE BEEKLEY, OF NORWOOD, OHIO, ASSIGNOR TO THE BULLOCK ELECTRIC MANUFACTURING COMPANY, -A 'CORPORATION OF OHIO.

i SERIES SH'UNT FOR DYNAMO-ELEGTRIC MACHINES.

Specication of Letters Patent.

Patented Nov. 12, 1907.

Applicaties sied November 29.19.05. serial No. 289,550.

IU Itis customary to provide compound wound machines with shunts of German-silver, connected across .theterminals of the series field winding, to shunt a f part ofjlthe armature 'current around -theseries winding v for the'purpose of obtaining a proper vcompounding .l effect. Usually -insuch machines it is difficult to pro- 1 vide the field magnets with exactly the proper number of series turns. In large machinesdesigned for heavy 'current loads it is generally'impossible `to do so for the reason thatvery few series turns are necessary. In

fact to obtain the proper series ampere turns with the vfull'load current frequently fractions of turns would be required. It is therefore customary to provide a greater number of series turns than would be required -ifthe full load current traversed the series winding and I to proyide a'.r series shunt across the series field terminals where'by a part of the current is shunted around the series winding to obtain t'leproper ampere turns.

fThe shunt referred `to is usually non-inductive, and

` -as commonly constructed, consists of a strip oi German- 'A 30 'silver wound back and forth around porcelain tubes l--mounted in two parallel plates of insulation. The istrip isthiriand wide to obtain the proper resistance j and heat radiating effects. i

The above type of shunt is non-adjustable. It is .customary therefore to Vcarry in stock a 'large number ,of Vshunts of different sizes and capacities, in order that ythe proper compounding' effect may be obtained foreach individual machine. In some cases if the resistance of a particular shunt'is too great, portions of the resistance material are sheared off until a strip oithe proper resistance is obtained.l In the latter case an unnecessarily large shunt frame is used. This is ob l jectionable for the reason that the shunt is usually ati cached to the frame of the machine.`

" The object of my invention 1s to provide a shunt the frameof which can be adjusted for any desired length f of resistance material. v

AIn carrying out my invention I mount the strip of resistance material'in. a sectional frame, whereby the size of the latter may be increased or decreased at will for any length-of resistancematerial.

More specifically considered, my invention consists in a series-'shunt having a zig-zag or looped resistance metal, a

substantially rectangular frame for the strip 5155; comprising four metal castings forl the corners of the4 frame through which castings pass two 'pairs of longitudinal parallel4 bolts each pair of which pass through opposite ends of the same corner castings, a plurality of insulatingblocks mounted on each of the bolts, insulated rodsvmoufnted inthe blocks said rods being in two opposite parallel sets, said resistance strip being looped about the insulated rods, and end-bolts passing through the metal castings at right angles to the aforesaid bolts for spreading'apart the two pairs of longi-I" tudinal bolts and blocks supported thereon, to put resistance strip under tension. I

For better understanding of my invention, reference is had to the accompanying' drawings, in which Figure l is an elevation of luy shunt; Fig. 2 is a plan view of thesame; and Fig. 3 is an endview ofthe same. Referring to the figures of the drawing, I have shown at l0 a long iiexible strip of resistance material, preferably German-silver. v This resistance strip is Zig-zaged or wound back and forth as shown so that the shunt will be compact. The strip is thin and wide so'that the resistance will be high and the heat radiation suflicient to prevent an undesirable rise of temperature.

The supporting frame is rectangular in shape, and consists of four similar cast metal corner pieces ll. mounted on four long longitudinal bolts l2 and four shorter transverse bolts I3. As is clear from the drawings each cast metal corner piece is provided with two pairs of openings to receive the bolts, the holes of one pair being arranged at iight angles to the holes of the other pair. Each cast metal cornet` piece 1l is provid'ed with a perforatedlug I4 by means of which -the shunt may be attached to a support. l'

Mounted on each bolt l2 are a number of blocks l5 preferably of insulating material as fiber.' The blocks l5 are arranged side by side and there is au equal number on each bolt. Each block l5 has a holevor opening to receive the supporting bolt l2, and an opening arranged at right angles to the first mentioned opening to receive an insulated rod 1G on which one section or loopof the resistance stlip l0 is supported. l have, in this case, shown seven fiber blocks on each bolt. Each -of the rods 16,'about which the resistancematelial l0 is looped, is mounted in two opposite insulating supporting blocks l5, and is held in place by a nut 16a. As is clear from the drawings; the rods are all parallel to each other and are arranged in two sets, the sets being in parallel planesv Mounted on each'rod is a tube of insulating material 17 preferablyof `porcelain. Thesev tubes are all of equal length, and hold the inner ends o the blocks the. proper distance apart. Each pair of insulating blocks 15, and the insulated rod- I6- The resistance strip l() is wrapped bar :lr and. forth around all the tubes and each free end is fastened to the last adjacent section or portion extending between two tubes by means ol' a clamp 18. By means o these clamps the ends of the resistance strip can be connected to the terminals (not shown) of the series iield winding.

The longitudinal bolts are provided. at both ends with tightening nuts 19,by means of which, the liber blocks can be held. closely together. The shorter bolts 13 are each provided with .four nuts'20, located on both sides ol' the corner members ll. By .means of these nuts 270, and particularly the nutsuonltlie inner sides of -the corner members, rthe two sets of .longitudinal bolts l2, which carry the insulating blocks l5 and rods 16, can bc spread apart so to tighten or put tension in the loops o thercsistance strip l0.

Asis shown at 2l; the longitudinal bolts extend at one end of the shunt, beyond the corner members 1l.

The object of this is to permit the size of the frame to be increased without changing the bolts l2. Il' the resistance ol the strip l() is not suil'icient', the nuts 19 and 20 can be loosened and another set of insulating blocks l5 and supporting rods 16 can be added and the traine will then support a longer resistance strip. On the other hand, if the resistance is too higlrthe size of the frame can be reduced by removing a suitable number oi supporting blocks and rods. A portion of the resistance strip can be sheared ott' and the remainder mounted on the frame.` lt' is evident that longer or shorter bolts l2 canvbe substituted when 4the size of the shunt is increased or decreased.

llis seen that my improved shunt is simple in construction and compact. As the rame consists of a plurality ol' sections its size. can be easily and quickly adjusted nl will by increasing or decreasing the number oi' sections. .lt will only be necessary to carry in stock a few bolts of different sizes for shunts which will produce the proper compounding effects for machines of different sizes arid conditions of windings.

l do not wish to be conlined-lto the details shown, as i have illustrated only what I consider' the best ernbodiineni. of my. invention. It' desired each ol' the frame sections or units may be made ol a single ineinber.

l aim in my claims to cover Iall changes and inodilications which do not involve a departure from the spirit and scope oi luy invention.

What Icla-im as ,new and desirel to secure by Letters Patent is:

l. ln a series-shunt for dynamo-electric machines, a strip ol resistance material, a f 'ame comprising a plurality ol rrxnovablcv sections id strip beine wound or looped about said sections, and means lor holding said sections together and for placing iid strip under tension.

'2. ln a series-shunt for dynamo-electric machines. a looped or zag strip ot' resistance metal, a frame therefor compris ig a number of sections or blocks ol insulat- 4 trarne compri. i

stderr ing material, a plnralitjY or bolts passing through said sections or blocks, andv means for adjusting the relative posirion ol said liollisto place vthe strip 'under tensi i.

In a series -hunt for dynamo-electric machines, a looped or frame therefor comprising removable insulating blocks, and a plurality o1 n nllcl supporting rods about which said strip is looped, m aus lor supporting said blocks, and

means for adjusting the relative position of said supportprising u plurality of bolts and a support for same, insulating blocks mountedon said bolts, means jtor permitting` a variahleiunuber ot'blocks to be mounted on said bolts,

rods cari-lcd by said-blocks, said strip 'of resistance metal being loopcdabout said rods, and means for adjusting the frame-to pnt the vstrip under tension.

G. ln a series-shunt for dynamo-clectric machines, a looped or zigzag strip of resistance'metal, and a supporting frame therefor'comprising two pairs of longitudinal supporting bolts and 'a lplurality of remorableseciious mounted on the bolts of each pair, said strip beinglooped about said sections. l I

7. ln a series-shunt for dynamo-electric machiues,|a looped Yor zig-zag strip of resistance metal, a supporting frame comprising longitudinal supporting bolts, removable insulating sections mounted on said bolts, said bolts and sections being in two sets, the resistance strip being looped Vbetween the sections of each set, and means l'or forcing saidsets apart for putting the strip under tension.

8. In aseries-shunt for dynamo-electric machlues, a

looped or zi strip of resistance luster-inl, a supporting g two pairs of longitudinal bolts, a uumbcr or removable insulating blocksl mounted on cach bolt. transverse parallel insulated rods mounted in the blocks ot" cach pair. said strip being-looped around each insulated rod, and bolts for spreading apart the two pairs ol bolts and blocks thereon, to put the strip under tension. Y Si. lu a series-shunt for dynamo-'electric machines. a looped or zigzag strip oi' resistance metal, a substantially rectangular frame therefor comprising vour metal castings for'rhe corners ot the trame, four longitudinal parallel bolts passing through the castings two of said bolts pussing through opposite ends of the same castings, an equal number of removable insulating blocks mounted on cach of said longitudinal bolts between the castings, rods mounted in said insulating` blocks said rods being in two opposite parallel sets, insulating tubes surrounding each of said last named rods, said res .tance incral being looped about thc tubes of the two sets, and end bolts passing through the metal castings at right angles to thc aforos' id bolts ior spreadingy the castings apartio put the resistance strip under tension.

In testimony whereof I affix my signature, in thc proseuce of two witnesses.

HENRY CIYDE BEEHLEY.

Witnesses z Flu-co J. KINsur, Au'rrrun F. Knors.

strip oli resistance metal, a supporting- 

